Several recent clinical studies have described the side effect of radiation-induced dermatitis that occurs in the majority of cancer patients who receive radiotherapy. These same studies also report the lack of effective agents to prevent or treat this dermatitis. In some of these patients, the side effects are severe enough that they withdraw from further radiotherapy. Nonetheless, radiotherapy remains a standard and essential part of cancer treatment and cure. ProCertus has developed a topically applied treatment to diminish or eliminate the dermatitis associated with radiotherapy. In current animal proof of concept studies, ProCertus has shown a >90% reduction in radiation-induced dermatitis by pretreating animals with ProDermX, which is currently a research stage human pharmaceutical. This technology consists of a carrier vehicle that delivers a single active agent to the stem cells of the epidermis. The active agent, a proprietary "chemoprotective polyamine," physically protects cellular DNA while also inducing a G1 phase, cell cycle block. This strategy enables the stem cells within the stratum germinativum of the epidermis to survive the radiation exposure, and to continue to replenish the outer layers of the skin and thus maintain a patent skin surface. Though ProCertus scientists have already carried this product through animal model proof of concept, there remain several biological and pharmacological questions that need to be answered before human studies can be initiated. Three Specific Aims have been designed to address and answer these questions during the course of this Phase I SBIR project, which will then enable initial studies in human populations in future research. [unreadable] [unreadable]